The present invention relates to a process for producing indoline. Indoline ##STR2## is used as an intermmediate of indole ##STR3## which is a starting material for producing agricultural chemicals, medicines, dyes and others, or an intermediate of indoline derivatives.
It has been known to produce indoline by reducing o-nitrophenethyl alcohol with zinc and calcium chloride to produce o-aminophenethyl alcohol and performing a cyclization in the presence of hydrochloric acid as follows. ##STR4##
However, in the method, phenethyl alcohols are easily decomposed by heating and by-products of polymers are formed in the reaction and the deterioration of the catalyst is remarkable, disadvantegeously, whereby, it has been difficult to obtain indoline having high purity in high yield.